Procedures that reduce conditioned responses, such as extinction, continue to be widely used in treatment and control of emotional, pharmacologic, and behavior disorders. Their widespread use continues despite a lack of complete understanding of the processes underlying such treatments. The proposed experiments examine the processes underlying extinction of conditioned responding and other treatments that reduce or prevent conditioned responding such as blocking, as well as factors that encourage and discourage recovery from such treatments, including the influence of context manipulations, retention intervals, reinstatement treatments, and comparator processes. The potential application of the results of these experiments will serve to show whether recovery of conditioned responses, for example, fear a stimulus based on a traumatic episode, a conditioned drug effect, or an aversion to a food substance will be affected by factors such as contextual cues, reexperiencing cues related to the traumatic or aversion episode, and the influence of retention intervals on such memories. The Human Capital Initiative illustrates the importance of conditioning to developing tools for alleviating and understanding mental health disorders when it states: "We also known that learning and conditioning are involved in the impact of environmental factors in psychopathology. For example, post-traumatic stress disorder is triggered by extreme external stressors and is often alleviated by behavioral treatments using learning and conditioning techniques"(HCI, Report 3, Chapter 1). Moreover, some of the current work in the conditioning field most readily applied to therapeutic settings are experiments involving context, extinction of acquired associations, and the reinstatement of extinguished memories; and this describes much of the planned efforts describe in the present proposal.